Maven install error: Dependency could not be resolved

Question

I am using Maven 3.1.1. When I run mvn install I get the following error:

D:\spring source>mvn install
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building SpringDependencies 1.0
[INFO] ------------------------------------------------------------------------
Downloading: http://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-
dependency-plugin/2.8/maven-dependency-plugin-2.8.pom
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 0.648s
[INFO] Finished at: Mon Dec 16 15:01:47 IST 2013
[INFO] Final Memory: 4M/15M
[INFO] ------------------------------------------------------------------------
[ERROR] Plugin org.apache.maven.plugins:maven-dependency-plugin:2.8 or one of it
s dependencies could not be resolved: Failed to read artifact descriptor for org
.apache.maven.plugins:maven-dependency-plugin:jar:2.8: Could not transfer artifa
ct org.apache.maven.plugins:maven-dependency-plugin:pom:2.8 from/to central (htt
p://repo.maven.apache.org/maven2): repo.maven.apache.org: Unknown host repo.mave
n.apache.org -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e swit
ch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please rea
d the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/PluginResoluti
onException

My pom.xml is:

<project xmlns="http://maven.apache.org/POM/4.0.0" 
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>spring-source-download</groupId>
  <artifactId>SpringDependencies</artifactId>
  <version>1.0</version>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.0.0.RELEASE</version>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
          <artifactId>maven-dependency-plugin</artifactId>
            <version>3.1.1</version>
            <executions>
              <execution>
                <id>download-dependencies</id>
                  <phase>generate-resources</phase>
                    <goals>
                      <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                      <outputDirectory> ${project.build.directory}/dependencies </outputDirectory>
                    </configuration>
              </execution>
            </executions>
      </plugin>
    </plugins>
  </build>
</project>

This is duplicate of https://stackoverflow.com/questions/32523461/maven-plugin-or-one-of-its-dependencies-could-not-be-resolved/48779413#48779413 — Sampath, Feb 15 '18 at 04:38

arghtype · Answer 1 · 2018-11-14T17:26:03.920

14

Could not transfer artifact org.apache.maven.plugins:maven-dependency-plugin:pom:2.8 from/to central (http://repo.maven.apache.org/maven2): repo.maven.apache.org: Unknown host repo.maven.apache.org

It seems like your maven cannot access remote central repository.

Check if you have an established internet connection.
Check if you can access default maven repo http://repo.maven.apache.org/maven2 in your browser.
Check if you have correct configuration in <repositories> and <proxies> in your your settings.xml

edited Nov 14 '18 at 17:26

answered Dec 16 '13 at 13:19

arghtype

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1

My `` block is commented out. But I am using proxy server to connect to the Internet. So I think that's the problem. – khateeb Dec 17 '13 at 08:46
In settings.xml you could specify your proxy: block `` – arghtype Dec 17 '13 at 09:04
http://stackoverflow.com/a/35911314/758673 is a possible solution for this, as it worked for me. – prabhugs Mar 10 '16 at 08:38
1

To add to above points, the internet connection could be intermittently down. Try after few minutes. – lupchiazoem Jan 27 '19 at 02:05
@lupchiazoem yes, seems what you said was the case. So, would a net connection always be required to build the app? – user8395964 Nov 13 '22 at 05:32

score 4 · Answer 2 · edited Aug 04 '17 at 09:59

This error comes due to the proxy settings.

First of all, check whether you are able to connect to maven repository(http://repo1.maven.org/maven2) from browser.

Then update Maven proxy setting create/update a settings.xml in .m2 directory with following details:

 <proxies>
    <proxy>
      <active>true</active>
      <protocol>http</protocol>
      <host>{your proxy server host name}</host>
      <port>{your proxy server port}</port>
      <nonProxyHosts>maven</nonProxyHosts>
    </proxy>
  </proxies>

Solution given by Maven community: http://maven.apache.org/guides/mini/guide-proxies.html

score 4 · Answer 3 · answered Feb 15 '18 at 04:42

4

This is caused by corrupted maven or plugins folder. To resolve this:

Delete \.m2\repository\org\apache\maven
mvn dependency:resolve -X

answered Feb 15 '18 at 04:42

Sampath

119
1
4

score 4 · Answer 4 · answered Jul 02 '20 at 20:36

Where is my Settings.xml?

Windows users

It's in your C:/Users/<Username>/.m2/settings.xml

Also, this is for specific user. Global one can be present at :

<Maven-Installation-Directory>/conf/settings.xml

But changing the User one might solve the issue if you can't find the global one.

Also, equally important, go to Preferences in Eclipse/STS:

Goto Maven -> User Settings and verify if both global and user settings.xml files are mentioned in the properties, if not mention them by browsing.

1. Proxy Issue

Check Windows Proxy Setting. If there is any proxy which your computer is using then you need to add proxy settings in your settings.xml file too.

Just add this chunk of code in your settings.xml

<proxies>
   <proxy>
      <id>proxy-id</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>ca-something.net</host>
      <port>80</port>
      <nonProxyHosts>localhost|10.140.240.90.*</nonProxyHosts>
    </proxy>
  </proxies>

2. Protocol Issue

Visit http://repo.maven.apache.org/: If it says Https required.

Then, you need to add this chunk of code to your settings.xml inside <mirrors>

<mirror>
  <id>central-secure</id>
  <url>https://repo.maven.apache.org/maven2</url>
  <mirrorOf>central</mirrorOf>
</mirror>

Now it should be good to go.

3. None of the above works

Try disconnecting any company private VPN and try mvn clean build.

score 3 · Answer 5 · answered May 03 '21 at 17:55

3

Disconnect from VPN and then run the command.

answered May 03 '21 at 17:55

Andrew Koper

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score 0 · Answer 6 · answered Apr 25 '17 at 20:16

Probably a bit late to the party, but there appears to be an unknown host exception thrown out of maven even if the resource/dependency is unavailable at that address.

Which could mean that the problem may actually be that you have a transitive dependency that is pointing you to the wrong version of a jar (or one that is transitively included multiple times - one of which may be an unresolvable version). (I see it's looking for version 2.8 of the plugin but you specified version 3.1.1, so it's likely you have another dependency transitively including the wrong version).

You can exclude transitive inclusion of a dependency using the exclusions tag.

score 0 · Answer 7 · answered Mar 30 '18 at 11:15

This issue was resolved for us by providing the correct proxy host in .m2/settings.xml.

Example:

<proxies>
   <proxy>
      <id>XXXXXXXXXX</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>na-xxxx-proxy.na.xxxxxxxxxx.net</host>
      <port>80</port>
      <nonProxyHosts>localhost|10.140.240.90.*</nonProxyHosts>
    </proxy>
  </proxies>

Maven install error: Dependency could not be resolved

7 Answers7

Where is my Settings.xml?

Windows users

1. Proxy Issue

2. Protocol Issue

3. None of the above works

Linked

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